Municipal water supply systems usually bury their mains under public rights of way, such as streets or sidewalks. At spaced intervals throughout the system normally open, shut-off valves are incorporated for the purpose of isolating main breaks so they can be repaired.
These shut-off valves are frequently buried several feet beneath street grades in the lower-most regions of manholes. Manholes for the valves typically will be provided by cylindrical concrete casings having an internal diameter sufficient to permit a worker in the manhole to effect repairs of the valve. The more or less standard manhole casing has a lower internal diameter of approximately five feet and is topped by a cone tapering inwardly and upwardly to the size of a standard manhole cover. Manhole casings may be provided in different sizes and even so-called standard casings may vary in diameter by as much as several inches due to imprecise casting.
It is desirable to provide for manipulation of each shut-off valve between its "off" and "on" positions by a person at street level, in other words, without having to descend into the manhole. And, this requires that an extension be provided for the valve stem which is normally no more than a few inches to one foot long. Without some form of stabilization, a lengthy stem extension for a deeply buried valve has a tendency to flop around in the sizable manhole, making manipulation of the valve difficult.
Leo M. Lester, in his U.S. Pat. No. 4,915,125, granted Apr. 10, 1990, for "Valve Stem Extension Assembly" discloses a system for supporting a very long heavy valve stem extension within a support casing surrounding the extension. He proposes to bolt a series of bushing carrying brackets to the casing. The stem extension carries a series of collars which rest on the bushings and transfer the weight of the extension to the brackets. The assembly taught by this patent has no provision for adjustment of the brackets to accommodate different size casings or misaligned extensions.
U.S. Pat. No. 3,961,528, granted Jun. 8, 1976, to Stanley W. Ford for "Meter Setting Device" discloses the use of an extensible tubular member for supporting a water meter within a cement meter box. Although adjustable as to length, the tubular member must be custom fabricated to match each individual meter installation.
Similarly, U.S. Pat. No. 4,989,634, granted Feb. 5, 1991, to Raymond J. Rieseck for "Fuel Dispenser Catchment Box" discloses the use of an extensible supporting clamp for stabilizing an upwardly extending fuel pipe within a catchment. But, the apparatus disclosed makes no provision for compensating for misaligned piping.
There continues to be a need for a versatile, easily installed, stabilizer bar for stabilizing lengthy valve stem extensions within a manhole.